A. Field of the Invention
The present invention relates to the field of internal combustion engines, more specifically, a hydraulic valve train that features a variable lift and timing.
B. Discussion of the Prior Art
As a preliminary note, it should be stated that there is an ample amount of prior art that deals with internal combustion engines and valve trains. As will be discussed immediately below, no prior art discloses a hydraulic valve train that features, in addition to a master piston-pushrod-tappet-camshaft, a stroke limiter piston and variable camshaft that can adjust independent of the rpm and of which effectively varies the lift and timing of the valve by working in concert with the hydraulic pressure created adjacent said master piston.
The Decuir, Jr. Patent (U.S. Pat. No. 7,077,088) discloses an adjustable hydraulic cam and valve lift system for an internal combustion engine. However, the valve lift system is mechanically operated via a single overhead cam and does not include a hydraulically operated valve that is operated via a master piston; wherein a stroke limiter piston can adjust the hydraulic pressure to vary the lift of the valve irrespective of engine rpm.
The Kobayashi et al. Patent (U.S. Pat. No. 6,619,251) discloses a tappet for an internal combustion engine having a recess for storing lubricating oil beneath the camshaft lobe. However, the tappet and recess do not work in concert with a hydraulically operated valve and of which includes a variable lift mechanism involving a second camshaft and stroke limiter piston that can adjust the hydraulic pressure created by a master piston in order to provide a varying lift of a valve independent of engine RPM.
The Kawasaki et al. Patent (U.S. Pat. No. 5,572,963) discloses a hydraulic valve tappet having an oil reservoir. However, the hydraulic valve tappet is not a variable hydraulic valve train that can adjust the lift of the hydraulically operated valve.
The Camosso et al. Patent (U.S. Pat. No. 4,640,238) discloses an oil-tight hydraulic tappet for controlling an internal combsution engine valve. Again, the tappet is directed to controlling the valve, but does not adjust the hydraulic pressure produced by a master piston in order to vary the lift of a hydraulically operated valve independent of engine rpm.
The Barnard Patent (U.S. Pat. No. 5,857,438) discloses a hydraulically operated variable valve lift mechanism. However, the mechanism does not include, in addition to the tappet, pushrod, and master piston, a second variable camshaft and stroke limiter piston that can adjust the hydraulic pressure applied onto the valve independent of the engine rpm and master piston position.
The Skelley Patent (U.S. Pat. No. 4,502,426) discloses a variable lift and timing mechanism for an internal combustion engine. Again, the variable lift and timing mechanism does not integrate a second variable camshaft and stroke limiter piston that operate independent of an engine rpm to adjust the hydraulic pressure output onto a valve, and thus vary valve lift.
The Kosuda et al. Patent (U.S. Pat. No. 4,408,580) discloses a hydraulic valve lift device for an internal combustion engine that includes a lifter having an oil pressure chamber for the introduction of oil into the lifter bore mechanism. Again, the device does not integrate a second variable camshaft and stroke limiter piston that operates independent of an engine rpm to adjust the hydraulic pressure output onto a valve thereby adjusting valve lift.
While the above-described devices fulfill their respective and particular objects and requirements, they do not describe a hydraulic valve train that features, in addition to a master piston-pushrod-tappet-camshaft, a stroke limiter piston and variable camshaft that can adjust independent of the rpm and of which effectively varies the lift and timing of the valve by working in concert with the hydraulic pressure created adjacent said master piston. In this regard, the variable lift hydraulic valve train departs from the conventional concepts and designs of the prior art.